The invention pertains to a windshield wiper arm and a method of manufacturing it.
In the present windshield wiper assemblies, the wiper rod and the link of wiper arms are connected by a rivet. For this purpose both the link and the wiper rod have to be provided with apertures for the rivet body. Therefore additional manufacturing steps and tooling are necessary. The link surface can be easily damaged during the riveting operation, so that an additional varnishing is sometimes necessary. Furthermore, it is disadvantageous that the rivet head projects from the link surface and thus the wiper arm does not meet all requirements from a styling point of view.
One significant problem with wiper arms including a rivet connection is that the contact pressure brought about by the spring element, usually a pull spring, does not meet the requirements with respect to exactness. More specifically, the spacing of the aperture for the rivet body in the link from the junction point of the link on the fastening member is subject to tolerances. Additionally, the spacing between the aperture for the rivet body in the wiper rod and the aperture into which the pull spring is suspended will also vary with production tolerances. The production tolerances may add up such that the spacing between the suspension points of the pull spring on the fastening member and on the wiper rod does not have the required dimension. Since the spacing between the suspension points of the pull spring determines the contact pressure, the contact pressure will be affected.
German patents DE-OS Nos. 20 31 848, 21 52 977 and 21 59 267 teach wiper arms in which a rivet is not needed to connect the wiper rod and link but the wiper rod still has apertures into which projections engage which are cut out or pressed out of the link. In the wiper arm according to DE-OS No. 21 59 267, lugs are pressed out of the lateral surfaces of the wiper rod which engage corresponding grooves in the side walls of the link. In all of these wiper arms the stability of dimensions of the apertures and projections determine the spacing of the suspensions points and thus the contact pressure.
The invention is based on the problems of providing a wiper arm in which the suspension points of the spring element have a spacing which is exactly adjustable and which can be produced economically.